Any ebike with throttle will allow pedaling at the same time, so - cross this out.
Single gear is simpler to operate and more reliable - less parts to fail. It is also less enjoyable. For somebody who won't pedal much, and if the terrain is mostly flat, a single gear is enough, but 7-gear won't hurt - you just won't use the other 6.
The worst battery location for stability is on the rear rack - not a disaster but you will feel it sometimes. The best location is along the seatpost or on the downtube - like Ride1Up, Aventon, RAD City and many other.
Ride1Up is a good choice if you can do your own maintenance and minor repairs or find a shop nearby that would agree to work on it (or maybe there is a mobile Velofix coverage in your area).
Seniors have come to appreciate step-through frames - those that used to be called called "women bikes". Something like this:
Aventon Pace 350. They've raised the price to $1,100 now. No lights or rack, budget another $50-60 for that. It has mechanical disc brakes, adequate for this lightweight bike and 350W motor.
If you're heavy or need more hill-climbing ability, for $1,400 there is
Aventon Pace 500 with a motor a little bigger and battery lasting a little longer (same motor as in Ride1Up). With hydraulic brakes.
Aesthetically, I'm not thrilled with how the Pace frames look, there are better looking step-through frames but the price is often higher or it is an imported bike with low-quality parts and no support.
As a side-note, it amazes me when a company suddenly decides to call their product "the best of 2020", or "the best cruiser", or "an ultimate commuter". As if somebody has given them a Nobel prize
.
One more thing - except for demo models, don't count on getting any ebike for the next few months. It's all made in China, they had stopped all the production earlier this year and it will take time to clear the backlog orders.
